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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.2 05-June-07
5    ---------------------
6    
7     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
8        which is apparently normally available under Windows.
9    
10     2. Re-jig the pcregrep tests with different newline settings in an attempt
11        to make them independent of the local environment's newline setting.
12    
13     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
14    
15     4. Some of the "internals" tests were previously cut out when the link size
16        was not 2, because the output contained actual offsets. The recent new
17        "Z" feature of pcretest means that these can be cut out, making the tests
18        usable with all link sizes.
19    
20     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
21        stack recursion. This gives a massive performance boost under BSD, but just
22        a small improvement under Linux. However, it saves one field in the frame
23        in all cases.
24    
25     6. Added more features from the forthcoming Perl 5.10:
26    
27        (a) (?-n) (where n is a string of digits) is a relative subroutine or
28            recursion call. It refers to the nth most recently opened parentheses.
29    
30        (b) (?+n) is also a relative subroutine call; it refers to the nth next
31            to be opened parentheses.
32    
33        (c) Conditions that refer to capturing parentheses can be specified
34            relatively, for example, (?(-2)... or (?(+3)...
35    
36        (d) \K resets the start of the current match so that everything before
37            is not part of it.
38    
39        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
40    
41        (f) \g{name} is another synonym - part of Perl 5.10's unification of
42            reference syntax.
43    
44        (g) (?| introduces a group in which the numbering of parentheses in each
45            alternative starts with the same number.
46    
47        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
48    
49     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
50        PCRE_INFO_JCHANGED.
51    
52     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
53        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
54        for detecting groups that can match an empty string.
55    
56     9. A pattern with a very large number of alternatives (more than several
57        hundred) was running out of internal workspace during the pre-compile
58        phase, where pcre_compile() figures out how much memory will be needed. A
59        bit of new cunning has reduced the workspace needed for groups with
60        alternatives. The 1000-alternative test pattern now uses 12 bytes of
61        workspace instead of running out of the 4096 that are available.
62    
63    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
64    
65    11. Applied patch from Google to remove an optimization that didn't quite work.
66        The report of the bug said:
67    
68          pcrecpp::RE("a*").FullMatch("aaa") matches, while
69          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
70          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
71    
72    
73    Version 7.1 24-Apr-07
74    ---------------------
75    
76     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
77        that is more "standard", making use of automake and other Autotools. There
78        is some re-arrangement of the files and adjustment of comments consequent
79        on this.
80    
81     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
82        for recursive directory scanning broke on some systems because the files
83        are not scanned in any specific order and on different systems the order
84        was different. A call to "sort" has been inserted into RunGrepTest for the
85        approprate test as a short-term fix. In the longer term there may be an
86        alternative.
87    
88     3. I had an email from Eric Raymond about problems translating some of PCRE's
89        man pages to HTML (despite the fact that I distribute HTML pages, some
90        people do their own conversions for various reasons). The problems
91        concerned the use of low-level troff macros .br and .in. I have therefore
92        removed all such uses from the man pages (some were redundant, some could
93        be replaced by .nf/.fi pairs). The 132html script that I use to generate
94        HTML has been updated to handle .nf/.fi and to complain if it encounters
95        .br or .in.
96    
97     4. Updated comments in configure.ac that get placed in config.h.in and also
98        arranged for config.h to be included in the distribution, with the name
99        config.h.generic, for the benefit of those who have to compile without
100        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
101    
102     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
103        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
104        makevp.bat for the current PCRE, using the additional files
105        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
106    
107     6. A Windows user reported a minor discrepancy with test 2, which turned out
108        to be caused by a trailing space on an input line that had got lost in his
109        copy. The trailing space was an accident, so I've just removed it.
110    
111     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
112        that is needed.
113    
114     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
115        as "const" (a) because they are and (b) because it helps the PHP
116        maintainers who have recently made a script to detect big data structures
117        in the php code that should be moved to the .rodata section. I remembered
118        to update Builducptable as well, so it won't revert if ucptable.h is ever
119        re-created.
120    
121     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
122        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
123        order to be able to cut out the UTF-8 tables in the latter when UTF-8
124        support is not required. This saves 1.5-2K of code, which is important in
125        some applications.
126    
127        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
128        so as not to refer to the tables, even though these functions will never be
129        called when UTF-8 support is disabled. Otherwise there are problems with a
130        shared library.
131    
132    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
133    
134        (a) It was defining its arguments as char * instead of void *.
135    
136        (b) It was assuming that all moves were upwards in memory; this was true
137            a long time ago when I wrote it, but is no longer the case.
138    
139        The emulated memove() is provided for those environments that have neither
140        memmove() nor bcopy(). I didn't think anyone used it these days, but that
141        is clearly not the case, as these two bugs were recently reported.
142    
143    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
144        and Detrail to create the HTML documentation, the .txt form of the man
145        pages, and it removes trailing spaces from listed files. It also creates
146        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
147        case, it wraps all the #defines with #ifndefs. This script should be run
148        before "make dist".
149    
150    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
151        with Unicode property support.
152    
153        (a) For a maximizing quantifier, if the two different cases of the
154            character were of different lengths in their UTF-8 codings (there are
155            some cases like this - I found 11), and the matching function had to
156            back up over a mixture of the two cases, it incorrectly assumed they
157            were both the same length.
158    
159        (b) When PCRE was configured to use the heap rather than the stack for
160            recursion during matching, it was not correctly preserving the data for
161            the other case of a UTF-8 character when checking ahead for a match
162            while processing a minimizing repeat. If the check also involved
163            matching a wide character, but failed, corruption could cause an
164            erroneous result when trying to check for a repeat of the original
165            character.
166    
167    13. Some tidying changes to the testing mechanism:
168    
169        (a) The RunTest script now detects the internal link size and whether there
170            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
171            values substituted by "configure". (The RunGrepTest script already did
172            this for UTF-8.) The configure.ac script no longer substitutes the
173            relevant variables.
174    
175        (b) The debugging options /B and /D in pcretest show the compiled bytecode
176            with length and offset values. This means that the output is different
177            for different internal link sizes. Test 2 is skipped for link sizes
178            other than 2 because of this, bypassing the problem. Unfortunately,
179            there was also a test in test 3 (the locale tests) that used /B and
180            failed for link sizes other than 2. Rather than cut the whole test out,
181            I have added a new /Z option to pcretest that replaces the length and
182            offset values with spaces. This is now used to make test 3 independent
183            of link size. (Test 2 will be tidied up later.)
184    
185    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
186        segmentation fault instead of returning the appropriate error message.
187    
188    15. In multiline mode when the newline sequence was set to "any", the pattern
189        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
190        This doesn't seem right; it now treats the CRLF combination as the line
191        ending, and so does not match in that case. It's only a pattern such as ^$
192        that would hit this one: something like ^ABC$ would have failed after \r
193        and then tried again after \r\n.
194    
195    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
196        in an attempt to make files that differ only in their line terminators
197        compare equal. This works on Linux.
198    
199    17. Under certain error circumstances pcregrep might try to free random memory
200        as it exited. This is now fixed, thanks to valgrind.
201    
202    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
203        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
204        was because its rules for how to advance for /g after matching an empty
205        string at the end of a line did not allow for this case. They now check for
206        it specially.
207    
208    20. pcretest is supposed to handle patterns and data of any length, by
209        extending its buffers when necessary. It was getting this wrong when the
210        buffer for a data line had to be extended.
211    
212    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
213        CRLF as a newline sequence.
214    
215    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
216        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
217        I have nevertheless tidied it up.
218    
219    23. Added some casts to kill warnings from HP-UX ia64 compiler.
220    
221    24. Added a man page for pcre-config.
222    
223    
224    Version 7.0 19-Dec-06
225    ---------------------
226    
227     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
228        moving to gcc 4.1.1.
229    
230     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
231        sys/time.h, which is documented as needed for this function. It doesn't
232        seem to matter on Linux, but it showed up on some releases of OS X.
233    
234     3. It seems that there are systems where bytes whose values are greater than
235        127 match isprint() in the "C" locale. The "C" locale should be the
236        default when a C program starts up. In most systems, only ASCII printing
237        characters match isprint(). This difference caused the output from pcretest
238        to vary, making some of the tests fail. I have changed pcretest so that:
239    
240        (a) When it is outputting text in the compiled version of a pattern, bytes
241            other than 32-126 are always shown as hex escapes.
242    
243        (b) When it is outputting text that is a matched part of a subject string,
244            it does the same, unless a different locale has been set for the match
245            (using the /L modifier). In this case, it uses isprint() to decide.
246    
247     4. Fixed a major bug that caused incorrect computation of the amount of memory
248        required for a compiled pattern when options that changed within the
249        pattern affected the logic of the preliminary scan that determines the
250        length. The relevant options are -x, and -i in UTF-8 mode. The result was
251        that the computed length was too small. The symptoms of this bug were
252        either the PCRE error "internal error: code overflow" from pcre_compile(),
253        or a glibc crash with a message such as "pcretest: free(): invalid next
254        size (fast)". Examples of patterns that provoked this bug (shown in
255        pcretest format) are:
256    
257          /(?-x: )/x
258          /(?x)(?-x: \s*#\s*)/
259          /((?i)[\x{c0}])/8
260          /(?i:[\x{c0}])/8
261    
262        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
263        is now done differently.
264    
265     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
266        wrapper classes; (b) implement a new function in the C++ scanner that is
267        more efficient than the old way of doing things because it avoids levels of
268        recursion in the regex matching; (c) add a paragraph to the documentation
269        for the FullMatch() function.
270    
271     6. The escape sequence \n was being treated as whatever was defined as
272        "newline". Not only was this contrary to the documentation, which states
273        that \n is character 10 (hex 0A), but it also went horribly wrong when
274        "newline" was defined as CRLF. This has been fixed.
275    
276     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
277        was being set to -1 for the "end of line" case (supposedly a value that no
278        character can have). Though this value is never used (the check for end of
279        line is "zero bytes in current character"), it caused compiler complaints.
280        I've changed it to 0xffffffff.
281    
282     8. In pcre_version.c, the version string was being built by a sequence of
283        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
284        string (as it is for production releases) called a macro with an empty
285        argument. The C standard says the result of this is undefined. The gcc
286        compiler treats it as an empty string (which was what was wanted) but it is
287        reported that Visual C gives an error. The source has been hacked around to
288        avoid this problem.
289    
290     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
291        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
292        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
293        of them did).
294    
295    10. Originally, pcretest opened its input and output without "b"; then I was
296        told that "b" was needed in some environments, so it was added for release
297        5.0 to both the input and output. (It makes no difference on Unix-like
298        systems.) Later I was told that it is wrong for the input on Windows. I've
299        now abstracted the modes into two macros, to make it easier to fiddle with
300        them, and removed "b" from the input mode under Windows.
301    
302    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
303    
304    12. Added -help and --help to pcretest as an official way of being reminded
305        of the options.
306    
307    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
308        and pcrecpp.cc because they annoy compilers at high warning levels.
309    
310    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
311    
312    15. Fixed an occurrence of == in configure.ac that should have been = (shell
313        scripts are not C programs :-) and which was not noticed because it works
314        on Linux.
315    
316    16. pcretest is supposed to handle any length of pattern and data line (as one
317        line or as a continued sequence of lines) by extending its input buffer if
318        necessary. This feature was broken for very long pattern lines, leading to
319        a string of junk being passed to pcre_compile() if the pattern was longer
320        than about 50K.
321    
322    17. I have done a major re-factoring of the way pcre_compile() computes the
323        amount of memory needed for a compiled pattern. Previously, there was code
324        that made a preliminary scan of the pattern in order to do this. That was
325        OK when PCRE was new, but as the facilities have expanded, it has become
326        harder and harder to keep it in step with the real compile phase, and there
327        have been a number of bugs (see for example, 4 above). I have now found a
328        cunning way of running the real compile function in a "fake" mode that
329        enables it to compute how much memory it would need, while actually only
330        ever using a few hundred bytes of working memory and without too many
331        tests of the mode. This should make future maintenance and development
332        easier. A side effect of this work is that the limit of 200 on the nesting
333        depth of parentheses has been removed (though this was never a serious
334        limitation, I suspect). However, there is a downside: pcre_compile() now
335        runs more slowly than before (30% or more, depending on the pattern). I
336        hope this isn't a big issue. There is no effect on runtime performance.
337    
338    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
339        newline (only possible for the last line of a file) and it was a
340        pattern that set a locale (followed by /Lsomething), pcretest crashed.
341    
342    19. Added additional timing features to pcretest. (1) The -tm option now times
343        matching only, not compiling. (2) Both -t and -tm can be followed, as a
344        separate command line item, by a number that specifies the number of
345        repeats to use when timing. The default is 50000; this gives better
346        precision, but takes uncomfortably long for very large patterns.
347    
348    20. Extended pcre_study() to be more clever in cases where a branch of a
349        subpattern has no definite first character. For example, (a*|b*)[cd] would
350        previously give no result from pcre_study(). Now it recognizes that the
351        first character must be a, b, c, or d.
352    
353    21. There was an incorrect error "recursive call could loop indefinitely" if
354        a subpattern (or the entire pattern) that was being tested for matching an
355        empty string contained only one non-empty item after a nested subpattern.
356        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
357        incorrectly, because the \d was being skipped in the check.
358    
359    22. The pcretest program now has a new pattern option /B and a command line
360        option -b, which is equivalent to adding /B to every pattern. This causes
361        it to show the compiled bytecode, without the additional information that
362        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
363        is the same as /B/I).
364    
365    23. A new optimization is now able automatically to treat some sequences such
366        as a*b as a*+b. More specifically, if something simple (such as a character
367        or a simple class like \d) has an unlimited quantifier, and is followed by
368        something that cannot possibly match the quantified thing, the quantifier
369        is automatically "possessified".
370    
371    24. A recursive reference to a subpattern whose number was greater than 39
372        went wrong under certain circumstances in UTF-8 mode. This bug could also
373        have affected the operation of pcre_study().
374    
375    25. Realized that a little bit of performance could be had by replacing
376        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
377    
378    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
379    
380    27. Possessive quantifiers such as a++ were previously implemented by turning
381        them into atomic groups such as ($>a+). Now they have their own opcodes,
382        which improves performance. This includes the automatically created ones
383        from 23 above.
384    
385    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
386        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
387        the first matched character to be a colon. This applied both to named and
388        numbered groups.
389    
390    29. The ucpinternal.h header file was missing its idempotency #ifdef.
391    
392    30. I was sent a "project" file called libpcre.a.dev which I understand makes
393        building PCRE on Windows easier, so I have included it in the distribution.
394    
395    31. There is now a check in pcretest against a ridiculously large number being
396        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
397        loop, the loop is abandoned.
398    
399    32. Forward references to subpatterns in conditions such as (?(2)...) where
400        subpattern 2 is defined later cause pcre_compile() to search forwards in
401        the pattern for the relevant set of parentheses. This search went wrong
402        when there were unescaped parentheses in a character class, parentheses
403        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
404    
405    33. "Subroutine" calls and backreferences were previously restricted to
406        referencing subpatterns earlier in the regex. This restriction has now
407        been removed.
408    
409    34. Added a number of extra features that are going to be in Perl 5.10. On the
410        whole, these are just syntactic alternatives for features that PCRE had
411        previously implemented using the Python syntax or my own invention. The
412        other formats are all retained for compatibility.
413    
414        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
415            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
416            also .NET compatible.
417    
418        (b) A recursion or subroutine call to a named group can now be defined as
419            (?&name) as well as (?P>name).
420    
421        (c) A backreference to a named group can now be defined as \k<name> or
422            \k'name' as well as (?P=name). The new forms, as well as being in Perl
423            5.10, are also .NET compatible.
424    
425        (d) A conditional reference to a named group can now use the syntax
426            (?(<name>) or (?('name') as well as (?(name).
427    
428        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
429            groups (named and numbered) that are never evaluated inline, but can be
430            called as "subroutines" from elsewhere. In effect, the DEFINE condition
431            is always false. There may be only one alternative in such a group.
432    
433        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
434            as the simple (?(R). The condition is true only if the most recent
435            recursion is that of the given number or name. It does not search out
436            through the entire recursion stack.
437    
438        (g) The escape \gN or \g{N} has been added, where N is a positive or
439            negative number, specifying an absolute or relative reference.
440    
441    35. Tidied to get rid of some further signed/unsigned compiler warnings and
442        some "unreachable code" warnings.
443    
444    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
445        things, this adds five new scripts.
446    
447    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
448        There were also incompatibilities regarding the handling of \Q..\E inside
449        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
450        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
451    
452    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
453        matches an empty string, and forcibly breaks the loop. There were bugs in
454        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
455        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
456        separate and independent bugs (that affected different cases) have been
457        fixed.
458    
459    39. Refactored the code to abolish the use of different opcodes for small
460        capturing bracket numbers. This is a tidy that I avoided doing when I
461        removed the limit on the number of capturing brackets for 3.5 back in 2001.
462        The new approach is not only tidier, it makes it possible to reduce the
463        memory needed to fix the previous bug (38).
464    
465    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
466        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
467        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
468        mode.
469    
470    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
471        report.
472    
473    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
474        copy construction and assignment in the C++ wrapper.
475    
476    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
477        couple of bugs that could have given wrong results in the "--newline=crlf"
478        case.
479    
480    44. Added a number of casts and did some reorganization of signed/unsigned int
481        variables following suggestions from Dair Grant. Also renamed the variable
482        "this" as "item" because it is a C++ keyword.
483    
484    45. Arranged for dftables to add
485    
486          #include "pcre_internal.h"
487    
488        to pcre_chartables.c because without it, gcc 4.x may remove the array
489        definition from the final binary if PCRE is built into a static library and
490        dead code stripping is activated.
491    
492    46. For an unanchored pattern, if a match attempt fails at the start of a
493        newline sequence, and the newline setting is CRLF or ANY, and the next two
494        characters are CRLF, advance by two characters instead of one.
495    
496    
497    Version 6.7 04-Jul-06
498    ---------------------
499    
500     1. In order to handle tests when input lines are enormously long, pcretest has
501        been re-factored so that it automatically extends its buffers when
502        necessary. The code is crude, but this _is_ just a test program. The
503        default size has been increased from 32K to 50K.
504    
505     2. The code in pcre_study() was using the value of the re argument before
506        testing it for NULL. (Of course, in any sensible call of the function, it
507        won't be NULL.)
508    
509     3. The memmove() emulation function in pcre_internal.h, which is used on
510        systems that lack both memmove() and bcopy() - that is, hardly ever -
511        was missing a "static" storage class specifier.
512    
513     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
514        containing an extended class (one that cannot be represented by a bitmap
515        because it contains high-valued characters or Unicode property items, e.g.
516        [\pZ]). Almost always one would set UTF-8 mode when processing such a
517        pattern, but PCRE should not loop if you do not (it no longer does).
518        [Detail: two cases were found: (a) a repeated subpattern containing an
519        extended class; (b) a recursive reference to a subpattern that followed a
520        previous extended class. It wasn't skipping over the extended class
521        correctly when UTF-8 mode was not set.]
522    
523     5. A negated single-character class was not being recognized as fixed-length
524        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
525        compile error "lookbehind assertion is not fixed length".
526    
527     6. The RunPerlTest auxiliary script was showing an unexpected difference
528        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
529        write a Perl script that can interpret lines of an input file either as
530        byte characters or as UTF-8, which is what "perltest" was being required to
531        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
532        can't do is switch easily at run time between having the "use utf8;" pragma
533        or not. In the end, I fudged it by using the RunPerlTest script to insert
534        "use utf8;" explicitly for the UTF-8 tests.
535    
536     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
537        the end of the subject string, contrary to the documentation and to what
538        Perl does. This was true of both matching functions. Now it matches only at
539        the start of the subject and immediately after *internal* newlines.
540    
541     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
542        a pointer to an int instead of a pointer to an unsigned long int. This
543        caused problems on 64-bit systems.
544    
545     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
546        instance of the 'standard' template library not being so standard".
547    
548    10. There was no check on the number of named subpatterns nor the maximum
549        length of a subpattern name. The product of these values is used to compute
550        the size of the memory block for a compiled pattern. By supplying a very
551        long subpattern name and a large number of named subpatterns, the size
552        computation could be caused to overflow. This is now prevented by limiting
553        the length of names to 32 characters, and the number of named subpatterns
554        to 10,000.
555    
556    11. Subpatterns that are repeated with specific counts have to be replicated in
557        the compiled pattern. The size of memory for this was computed from the
558        length of the subpattern and the repeat count. The latter is limited to
559        65535, but there was no limit on the former, meaning that integer overflow
560        could in principle occur. The compiled length of a repeated subpattern is
561        now limited to 30,000 bytes in order to prevent this.
562    
563    12. Added the optional facility to have named substrings with the same name.
564    
565    13. Added the ability to use a named substring as a condition, using the
566        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
567        are numbers (not recommended). Forward references are permitted.
568    
569    14. Added forward references in named backreferences (if you see what I mean).
570    
571    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
572        pattern could run off the end of the subject. For example, the pattern
573        "(?s)(.{1,5})"8 did this with the subject "ab".
574    
575    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
576        PCRE_CASELESS was set when matching characters that were quantified with ?
577        or *.
578    
579    17. A character class other than a single negated character that had a minimum
580        but no maximum quantifier - for example [ab]{6,} - was not handled
581        correctly by pce_dfa_exec(). It would match only one character.
582    
583    18. A valid (though odd) pattern that looked like a POSIX character
584        class but used an invalid character after [ (for example [[,abc,]]) caused
585        pcre_compile() to give the error "Failed: internal error: code overflow" or
586        in some cases to crash with a glibc free() error. This could even happen if
587        the pattern terminated after [[ but there just happened to be a sequence of
588        letters, a binary zero, and a closing ] in the memory that followed.
589    
590    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
591        over the years. Originally (before any Unicode support), just the bottom 8
592        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
593        output from "man perlunicode" includes this:
594    
595          The regular expression compiler produces polymorphic opcodes.  That
596          is, the pattern adapts to the data and automatically switches to
597          the Unicode character scheme when presented with Unicode data--or
598          instead uses a traditional byte scheme when presented with byte
599          data.
600    
601        Sadly, a wide octal escape does not cause a switch, and in a string with
602        no other multibyte characters, these octal escapes are treated as before.
603        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
604        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
605        Unicode string.
606    
607        I have not perpetrated such confusion in PCRE. Up till now, it took just
608        the bottom 8 bits, as in old Perl. I have now made octal escapes with
609        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
610        translate to the appropriate multibyte character.
611    
612    29. Applied some refactoring to reduce the number of warnings from Microsoft
613        and Borland compilers. This has included removing the fudge introduced
614        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
615        a warning about an unused variable.
616    
617    21. PCRE has not included VT (character 0x0b) in the set of whitespace
618        characters since release 4.0, because Perl (from release 5.004) does not.
619        [Or at least, is documented not to: some releases seem to be in conflict
620        with the documentation.] However, when a pattern was studied with
621        pcre_study() and all its branches started with \s, PCRE still included VT
622        as a possible starting character. Of course, this did no harm; it just
623        caused an unnecessary match attempt.
624    
625    22. Removed a now-redundant internal flag bit that recorded the fact that case
626        dependency changed within the pattern. This was once needed for "required
627        byte" processing, but is no longer used. This recovers a now-scarce options
628        bit. Also moved the least significant internal flag bit to the most-
629        significant bit of the word, which was not previously used (hangover from
630        the days when it was an int rather than a uint) to free up another bit for
631        the future.
632    
633    23. Added support for CRLF line endings as well as CR and LF. As well as the
634        default being selectable at build time, it can now be changed at runtime
635        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
636        specify that it is scanning data with non-default line endings.
637    
638    24. Changed the definition of CXXLINK to make it agree with the definition of
639        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
640    
641    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
642        recursions. This makes a big different to stack usage for some patterns.
643    
644    26. If a subpattern containing a named recursion or subroutine reference such
645        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
646        the space required for the compiled pattern went wrong and gave too small a
647        value. Depending on the environment, this could lead to "Failed: internal
648        error: code overflow at offset 49" or "glibc detected double free or
649        corruption" errors.
650    
651    27. Applied patches from Google (a) to support the new newline modes and (b) to
652        advance over multibyte UTF-8 characters in GlobalReplace.
653    
654    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
655        difference for some implementation of PCRE in some Windows version.
656    
657    29. Added some extra testing facilities to pcretest:
658    
659        \q<number>   in a data line sets the "match limit" value
660        \Q<number>   in a data line sets the "match recursion limt" value
661        -S <number>  sets the stack size, where <number> is in megabytes
662    
663        The -S option isn't available for Windows.
664    
665    
666    Version 6.6 06-Feb-06
667    ---------------------
668    
669     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
670        in pcreposix.h. I have copied the definition from pcre.h.
671    
672     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
673        because pcre.h is no longer a built file.
674    
675     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
676        not normally included in the compiled code.
677    
678    
679  Version 6.5 01-Feb-06  Version 6.5 01-Feb-06
680  ---------------------  ---------------------
681    

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